Grade and recovery of eddy current separation can be estimated on the basis of trajectory simulations for particles of simple shapes. In order to do so, the feed is characterized in terms of a small set of test-particles, each test-particle representing a fraction of the feed of a given size, shape and material. In this paper, the grade and recovery curve predicted for a sample from the 616mm non-ferrous fraction of car scrap is compared with experimental data. The results indicate that it may be possible to automatically control eddy current separators on the basis of such predictions.